import java.util.Scanner;

public class Dem20 {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        String s=sc.nextLine();
        StringBuilder st=new StringBuilder(s);
        st.reverse();
        if(s.equals(st.toString())){
            System.out.println("是反转字符串");
        }else{
            System.out.println("不是反转字符串");
        }

    }
}
